Definitions of placid:

• adjective:   free from disturbance

  Example: "A ribbon of sand between the angry sea and the placid bay"

• adjective:   without untoward incident or disruption

  Example: "A placid existence"

• adjective:   taking life easy

  Example: "An air of placid sufficiency"

• adjective:   not easily irritated

  Example: "Not everyone shared his placid temperament"